Loading unit for surgical instruments with low profile pushers

ABSTRACT

A loading unit including double pushers and double retention cavities is disclosed. At least one double pusher includes a first body portion having a first upper surface configured to engage a portion of a first fastener, a second body portion having a second upper surface configured to engage a portion of a second fastener, and a bridge interconnecting the first body portion and the second body portion. Each of the first upper surface and the second upper surface defining an acute angle with respect to a longitudinal axis. At least one double retention cavity includes a first retention guiding surface configured to engage a proximal pusher guiding surface of the first body portion of the double pusher retained therein, and a second retention guiding surface configured to engage a distal pusher guiding surface of the first body portion of the double pusher retained therein.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims the benefit of, priority to, and is a Continuation application of U.S. patent application Ser. No. 15/439,312, filed on Feb. 22, 2017, the entire content of which being incorporated by reference herein.

BACKGROUND Technical Field

The present disclosure relates generally to instruments for surgically joining tissue and, more specifically, to a loading unit for surgical instruments with low profile pushers

Various types of surgical instruments used to surgically join tissue are known in the art, and are commonly used, for example, for closure of tissue or organs in transection, resection, anastomoses, for occlusion of organs in thoracic and abdominal procedures, and for electrosurgically fusing or sealing tissue.

One example of such a surgical instrument is a surgical stapling instrument, which may include an anvil assembly, a cartridge assembly for supporting an array of surgical fasteners, an approximation mechanism for approximating the cartridge and anvil assemblies, and a firing mechanism for ejecting the surgical fasteners from the cartridge assembly.

Using a surgical stapling instrument, it is common for a surgeon to approximate the anvil and cartridge members. Next, the surgeon can fire the surgical stapling instrument to emplace surgical fasteners in tissue. Further, the surgeon may use the same instrument or a separate instrument to cut the tissue adjacent or between the row(s) of surgical fasteners.

Additionally, a loading unit (e.g., a single use loading unit or a disposable loading unit) may be attached to an elongated or endoscopic portion of a surgical stapling instrument. Such loading units allow surgical stapling instruments to have greater versatility. The loading units may be configured for a single use, and/or may be configured for multiple uses.

Further, end effectors and/or loading units are generally limited in size by various components contained therein. That is, while there may be a need for end effectors and/or loading units having diameters that are smaller than those typically available, the diameter of the end effector and/or loading unit is typically limited by the size, geometry and/or orientation of the pushers, I-beam, actuation sled, and fasteners, for example, contained therein.

SUMMARY

The present disclosure relates to a loading unit configured for engagement with a surgical instrument. The loading unit includes a proximal body portion, an end effector, an actuation sled, double pushers and double retention cavities. The proximal body portion defines a longitudinal axis. The end effector is disposed in mechanical cooperation with the proximal body portion, and includes a cartridge assembly and an anvil assembly. One of the cartridge assembly and the anvil assembly is movable with respect to the other of the cartridge assembly and the anvil assembly between an open position and an approximated position. The cartridge assembly is configured to house fasteners therein. The actuation sled is longitudinally translatable within the cartridge assembly. The double pushers are disposed within the cartridge assembly. At least one double pusher includes a first body portion having a first upper surface configured to engage a portion of first fastener, a second body portion having a second upper surface configured to engage a portion of a second fastener, and a bridge interconnecting the first body portion and the second body portion. The first body portion includes a proximal pusher guiding surface and a distal pusher guiding surface. Each of the first upper surface and the second upper surface defines an acute angle with respect to the longitudinal axis. The double retention cavities are disposed within the cartridge assembly, and each double retention cavity is configured to retain one double pusher therein. At least one double retention cavity includes a first retention guiding surface configured to engage the proximal pusher guiding surface of the first body portion of the double pusher retained therein, and a second retention guiding surface configured to engage the distal pusher guiding surface of the first body portion of the double pusher retained therein.

In disclosed embodiments, the at least one double pusher may include a first ramp disposed on a lower surface of the first body portion. The first ramp may be configured to be engaged by a first angled wedge of the actuation sled. It is also disclosed that the at least one double pusher may include a second ramp disposed on a lower surface of the second body portion. The second ramp may be configured to be engaged by a second angled wedge of the actuation sled. Additionally, it is disclosed that the first ramp may be parallel to the longitudinal axis, and the second ramp may be parallel to the longitudinal axis. It is further disclosed that the first ramp may be disposed directly beneath a portion of the upper surface of the first body portion, and that the second ramp may be disposed directly beneath a portion of the upper surface of the second body portion.

In embodiments, the acute angle may be between about 30° and about 60°.

It is also disclosed that the at least one double retention cavity may include a third retention guiding surface configured to engage the proximal pusher guiding surface of the second body portion of the double pusher retained therein, and a fourth retention guiding surface configured to engage the distal pusher guiding surface of the second body portion of the double pusher retained therein.

In disclosed embodiments, the bridge may interconnect a proximal portion of the first body portion with a distal portion of the second body portion.

It is further disclosed that an outer-most diameter of the end effector may be about 12 mm with the end effector in the approximated position. Additionally, it is disclosed that the loading unit may include fasteners retained at least partially within the cartridge assembly. At least one fastener may have a height of about 5 mm.

The present disclosure also relates to an end effector configured for use with a surgical instrument. The end effector includes a cartridge assembly, an anvil assembly, an actuation sled, pushers, and a plurality of fasteners. One of the cartridge assembly and the anvil assembly is movable with respect to the other of the cartridge assembly and the anvil assembly between an open position and an approximated position. The actuation sled is translatable along a longitudinal axis within the cartridge assembly. The pushers are disposed at least partially within the cartridge assembly and are configured to be selectively engaged by the actuation sled. At least one pusher has a first upper surface configured to engage a first fastener and a first ramp configured to be engaged by a first wedge of the actuation sled. The first upper surface is disposed at an acute angle with respect to the longitudinal axis. The first ramp is parallel to the longitudinal axis. The plurality of fasteners is retained at least partially within the cartridge assembly. Each fastener of the plurality of fasteners is disposed in contact with one pusher of the plurality of pushers, and each fastener of the plurality of fasteners includes a height of about 5 mm. An outer-most diameter of the end effector is about 12 mm.

In disclosed embodiments, the at least one pusher may include a second upper surface configured to engage a second fastener, and a second ramp may be configured to be engaged by a second wedge of the actuation sled. It is also disclosed that the first upper surface may be parallel to the second upper surface.

In embodiments, the first ramp may be disposed directly beneath a portion of the first upper surface. It is further disclosed that the second ramp may be disposed directly beneath a portion of the second upper surface.

It also disclosed that the acute angle may be between about 30° and about 60°.

In disclosed embodiments, the first upper surface may be included on a first body portion of the at least one pusher and the second upper surface may be included on a second body portion of the at least one pusher, and that the pusher may also include a bridge interconnecting a proximal portion of the first body portion with a distal portion of the second body portion.

DESCRIPTION OF THE DRAWINGS

Various embodiments of the present disclosure are illustrated herein with reference to the accompanying drawings, wherein:

FIG. 1 is a perspective view of a surgical instrument in accordance with an embodiment of the present disclosure;

FIG. 2 is a perspective view of a loading unit having an end effector in accordance with the present disclosure illustrating the end effector in an open position;

FIG. 3 is a side view of the loading unit of FIG. 2 illustrating the end effector in an approximated position;

FIG. 4 is a distal end view of a portion of the end effector of FIG. 3 ;

FIG. 5 illustrates the area of detail indicated in FIG. 2 ;

FIG. 5A illustrates the area of detail indicated in FIG. 5 ;

FIG. 5B is a top view of a cartridge assembly of the end effector of FIG. 5A;

FIG. 5C is a top view of a staple line resulting from the use of the end effector of FIG. 5 ;

FIG. 6 is a perspective view of a portion of a cartridge assembly of the end effector of FIG. 5B including a plurality of fasteners engaged therewith;

FIG. 7 is an assembly view a cartridge assembly of the end effector of FIG. 2 ;

FIG. 8 is a perspective view of two pairs of double pushers of the end effector of FIGS. 1-7 ;

FIG. 9 is a perspective view of an underside of one pair of double pushers of FIG. 8 ;

FIG. 10 is a cross-sectional view of one of the double pushers of FIGS. 8 and 9 ;

FIG. 11 is a perspective view of an actuation sled of the cartridge assembly of FIG. 2 and a pair of double pushers of FIG. 8 ;

FIG. 12 illustrates the area of detail indicated in FIG. 6 ;

FIG. 13A is a perspective view of the cartridge assembly of the end effector in accordance with the present disclosure and without pushers therein;

FIG. 13B illustrates the area of detail indicated in FIG. 13A;

FIG. 13C illustrates the area of detail indicated in FIG. 13A with the addition of pushers within the cartridge assembly;

FIG. 14 is a cut-away view of portions of the end effector taken along line 14-14 of FIG. 4 ;

FIG. 15 is a cut-away view of portions of the end effector taken along line 15-15 of FIG. 4 ;

FIG. 16 is a perspective view of a double pusher in accordance with embodiments of the present disclosure; and

FIG. 17 is a perspective view of a single pusher in accordance with embodiments of the present disclosure.

DETAILED DESCRIPTION

Embodiments of the presently disclosed surgical instrument, loading unit for use therewith, and cartridge assembly for use therewith, are described in detail with reference to the drawings, wherein like reference numerals designate corresponding elements in each of the several views. As is common in the art, the term “proximal” refers to that part or component closer to the user or operator, e.g., surgeon or physician, while the term “distal” refers to that part or component farther away from the user.

A surgical instrument of the present disclosure is indicated as reference numeral 100 in FIG. 1 . Generally, surgical instrument 100 includes a handle assembly 110, an elongated portion 120 extending distally from handle assembly 110, and a loading unit 200 disposed adjacent a distal end of elongated portion 120. While FIG. 1 illustrates surgical instrument 100 including a handle assembly including a movable handle 112 and a stationary handle, other types of handles can be used such as, for example, powered, motor-driven, hydraulic, ratcheting, etc. As used herein, “handle assembly” encompasses all types of handle assemblies. Loading unit 200 is releasably attachable to elongated portion 120 of surgical instrument 100, e.g., to allow surgical instrument 100 to have greater versatility. This arrangement allows the clinician to select a particular loading unit 200 for a given procedure. As used herein, “loading unit” encompasses both single use loading units (“SULU”) and disposable loading units (“DLU”). Additionally or alternatively, surgical instrument 100 may have a cartridge that is removable and replaceable in the reusable jaws of the surgical instrument 100.

Examples of loading units for use with a surgical stapling instrument are disclosed in commonly-owned U.S. Pat. No. 5,752,644 to Bolanos et al., the entire contents of which are hereby incorporated by reference herein. Further details of an endoscopic surgical stapling instrument are described in detail in commonly-owned U.S. Pat. No. 6,953,139 to Milliman et al., the entire contents of which are hereby incorporated by reference herein.

In surgical instrument 100 in accordance with the present disclosure, a firing rod (not shown) is moved distally in response to actuation of handle assembly 110 to deploy fasteners 600 (FIGS. 6 and 7 ). With reference to the embodiment illustrated in FIG. 1 , at least a partial actuation of movable handle 112 translates the firing rod longitudinally. Distal translation of the firing rod causes distal translation of a clamping member 500 (FIG. 7 ) to approximate at least one jaw member with respect to the other, as discussed in further detail below. Distal translation of clamping member 500 also causes corresponding translation of an actuation sled 520, which engages pushers 800 (FIG. 7 ) in a sequential manner, and which results in pushers 800 moving within retention cavities 1000 (FIG. 5A) of a cartridge assembly 400 to cause the ejection of fasteners 600 therefrom, as discussed in further detail below (FIG. 7 ).

With reference to FIG. 2 , loading unit 200 according to the present disclosure is shown. Loading unit 200 includes a proximal body portion 210 defining a longitudinal axis “A-A,” and a tool assembly or end effector 220 including a first jaw member or anvil assembly 300, and a second jaw member or cartridge assembly 400. Cartridge assembly 400 includes a cartridge 408 disposed within a cartridge channel 409 (FIG. 7 ). Proximal body portion 210 is configured to be removably attached to elongated portion 120 of surgical instrument 100 (FIG. 1 ) as will be discussed in detail hereinbelow. Additionally, end effector 220 is pivotable with respect to proximal body portion 210 (and longitudinal axis “A-A”).

Various features of loading unit 200 disclosed herein allow loading unit 200 to have a relatively small diameter “d” (e.g., about 12 mm) as compared with more conventional instruments having diameters of about 15 mm. As shown in FIGS. 3 and 4 , the diameter “d” of the loading unit 200, and end effector 220 in particular, is measured between a radially outer-most wall of anvil assembly 300 and a radially outer-most wall of cartridge assembly 400. Such a low profile allows loading unit 200 to be inserted into trocars or other access devices having similar inner diameters. It is contemplated that the presently disclosed end effector 220 can be inserted into openings in body tissue (e.g., incision or naturally occurring orifice) having a comparable diameter. As can be appreciated, such low profile loading units 200 are useful in pediatric surgeries and/or other tissue locations, for example.

Additionally, in the illustrated embodiments, a proximal portion 212 of proximal body portion 210 of loading unit 200 is sized and configured to engage elongated portion 120 of surgical instrument 100 (FIG. 1 ). It is envisioned that elongated portion 120 of surgical instrument 100 includes the same or similar diameter (e.g., about 12 mm) than the diameter “d” of loading unit 200, thus enabling greater versatility.

More particularly, with reference to FIGS. 2 and 3 , an insertion tip 202 of loading unit 200 is linearly insertable into the distal end of elongated portion 120 of surgical instrument 100 (FIG. 1 ). Nubs 204 of insertion tip 202 move linearly through slots (not shown) formed adjacent the distal end of elongated portion 120. Subsequently, loading unit 200 is rotated about the longitudinal axis “A-A” with respect to elongated portion 120 such that nubs 204 move transversely with respect to longitudinal axis “A-A” through the slots within elongated portion 120. Additionally, during engagement of loading unit 200 and elongated portion 120, the firing rod of handle assembly 110 engages a portion of a drive bar 510 (FIG. 7 ) of loading unit 200. As shown in FIG. 7 , a distal end of drive bar 510 is coupled to clamping member 500.

With reference to FIG. 7 , clamping member 500 includes an I-shaped cross-section, including a top portion 502, which is configured to engage anvil assembly 300 (FIG. 2 ), a bottom portion 504, which is configured to engage cartridge assembly 400, and a vertical portion 503, which connects top portion 502 and bottom portion 504, and which may include a cutting edge 506 on its distal or leading surface. Further, distal advancement of clamping member 500 through end effector 220 causes bottom portion 504 to contact a camming surface 402 (FIG. 3 ) of cartridge assembly 400. Continued distal advancement of clamping member 500 thus causes cartridge assembly 400 to pivot with respect to anvil assembly 300 from its open position (FIG. 2 ) toward its approximated position (FIG. 3 ). It is further envisioned that anvil assembly 300 may pivot with respect to a stationary cartridge assembly 400. Thus, a predetermined amount of distal travel of the firing rod, and thus drive bar 510, causes approximation of the jaw members. Additionally, cutting edge 506 of clamping member 500, if included on clamping member 500, severs tissue disposed between the jaw members (after the tissue has been fastened) as cutting edge 506 travels through a knife channel 401 of cartridge assembly 400 (FIGS. 5-6 ). In embodiments where end effector 220 is curved, knife channel 401 may define a longitudinal axis.

With further regard to actuation sled 520, distal translation of actuation sled 520 sequentially engages pushers 800, and causes pushers 800 to move in the general direction of arrow “B” (FIG. 7 ) and eject fasteners 600 toward anvil assembly 300 (FIG. 3 ). As noted above, subsequent to the ejection of fasteners 600, cutting edge 506 of clamping member 500 may sever the stapled tissue.

With particular reference to FIGS. 7, 14 and 15 , further details of actuation sled 520 are disclosed. Actuation sled 520 includes four angled wedges 524 a, 524 b, 524 c, 524 d, each of which is configured to contact a camming surface, angled surface or ramp 840, 850 of pushers 800, as discussed below. Engagement between wedges 524 a, 524 b, 524 c, 524 d of actuation sled 520 and camming surfaces 840, 850 of pushers 800 causes pushers 800 to move in the general direction of arrow “B” (FIG. 7 ), which results in ejection of fasteners 600 from retention cavities 1000 of cartridge assembly 400, and toward respective staple-forming pockets (not shown) of anvil assembly 300 (e.g., through tissue held between the jaw members).

Referring now to FIGS. 8-11 , further details of pushers 800 are disclosed. Generally, pushers 800 include a plurality of double pushers, with each double pusher retained within a retention cavity 1000 (FIGS. 14 and 15 ) of cartridge assembly 400.

With particular reference to FIGS. 7 and 8 , pushers 800 include a first double pusher 800 a and a second double pusher 800 b. First double pushers 800 a are disposed on a first side of knife channel 401 of cartridge assembly 400 and second double pushers 800 b are disposed on a second side of knife channel 401 of cartridge assembly 400. Each double pusher 800 a is configured to engage two fasteners 600: one fastener 600 in an inner row and one fastener 600 in an outer row on the first side of knife channel 401. Each double pusher 800 b is configured to engage two fasteners 600: one fasteners 600 in an inner row and one fastener 600 in an outer row on the second side of knife channel 401. First double pusher 800 a is a mirror image of second double pusher 800 b. Accordingly, only the details of one double pusher 800 a are discussed herein, and are generally referred to as pusher or double pusher 800.

With reference to FIGS. 8 and 9 , double pusher 800 includes a first body portion 810, a second body portion 820, a bridge 830, first camming member, angled surface or ramp 840, and second camming member, angled surface or ramp 850. Double pusher 800 is positioned within cartridge assembly 400 such that first body portion 810 and second body portion 820 are disposed at an angle α (see FIG. 5C) with respect to the longitudinal axis “A-A.” The angle α may be between about 30° and about 60°, for example, although larger and smaller angles are also contemplated.

Additionally, first body portion 810 includes an arcuate proximal edge 813 and an arcuate distal edge 814, and second body portion 820 includes an arcuate proximal edge 823 and an arcuate distal edge 824 (FIG. 9 ). Each proximal edge 813, 823 and distal edge 814, 824 is configured to engage corresponding portions of retention cavity 1000 (FIG. 5 ) to help guide and/or align the travel of double pusher 800 with respect to cartridge assembly 400. Bridge 830 extends perpendicularly between and interconnects first body portion 810 and second body portion 820. More particularly, bridge 830 interconnects a proximal portion of first body portion 810 and a distal portion of second body portion 820.

With reference to FIG. 8 , an upper surface or channel 815 of first body portion 810 and an upper surface or channel 825 of second body portion 820 of double pusher 800 are each configured and dimensioned to engage a backspan 602 (FIG. 11 ) of one fastener 600. Upper channels 815 and 825 include an arcuate cross-section, which helps to optimize engagement with a cylindrical portion of backspan 602, for example.

Referring now to FIGS. 10 and 11 , wedges 524 a-d are configured to engage first and second camming members 840, 850 of double pusher 800. More particularly, wedge 524 b is configured to engage first camming member 840 of first double pusher 800 a, wedge 524 c is configured to engage first camming member 840 of second double pusher 800 b, wedge 524 a is configured to engage second camming member 850 of first double pusher 800 a, and wedge 524 d is configured to engage second camming member 850 of second double pusher 800 b.

In use, distal movement of actuation sled 520 through cartridge assembly 400 causes wedges 524 b and 524 c of actuation sled 520 to contact first camming members 840 of double pushers 800 a, 800 b, and causes wedges 524 a and 524 d to contact second camming members 850 of double pushers 800 a, 800 b, which consequently causes double pushers 800 a, 800 b to move in the general direction of arrow “B” (FIG. 7 ). This movement of each double pusher 800 a, 800 b causes two corresponding fasteners 600 to be ejected from retention cavities 1000 of cartridge assembly 400.

With reference to FIG. 10 , a height “h1” of upper channel 815 of first body portion 810 with respect to lower surface 802 of double pusher 800 is larger than a height “h2” of upper channel 825 of second body portion 820 with respect to the lower surface 802 of double pusher 800. It is disclosed that height “h1” is between about 1.42 mm and about 1.62 mm (e.g., equal to about 1.52 mm), and that height “h2” is between about 1.04 mm and about 1.24 mm (e.g., equal to about 1.14 mm).

Additionally, with reference to FIGS. 8 and 9 , first camming member 840 is disposed at an acute angle (e.g., between about 30° and about 60°, for example) with respect to upper channel 815 of first body portion 810, and second camming member 850 is disposed at an acute angle (e.g., between about 30° and about 60°, for example) with respect to upper channel 825 of second body portion 820. First camming member 840 and second camming member 850 are each parallel to knife channel 401 and longitudinal axis “A-A”. Further, a portion of first camming member 840 is positioned directly beneath upper channel 815 of first body portion 810, and a portion of second camming member 850 is positioned directly beneath upper channel 825 of second body portion 820. The positioning of camming members 840, 850 beneath upper channels 815, 825, respectively, enables bridge 830 to have a reduced height (with respect to a lower surface 802 (FIG. 10 ) of double pusher 800) since there is no camming surface beneath bridge 830. Further, the reduced height of bridge 830 enables pusher 800 to have a reduced height with respect to previous types of pushers. Since the height of pushers 800 is relatively small, the amount of distance that pushers 800 can travel (i.e., “pusher stroke”) is relatively large. Such a large “pusher stroke” allows larger fasteners 600 (e.g., having a height of about 5 mm) to be used in connection with cartridge assembly 400. Further, the pushers 800 are configured to eject fasteners 600 in a herringbone-like pattern, as shown in FIG. 5C. The resulting staple line includes fasteners 600 disposed at an acute angle α (e.g., between about 30° and about 60°, for example) with respect to longitudinal axis “A-A.”

With reference to FIG. 8 , first body portion 810 of pusher 800 includes a first guidance block 870, and second body portion 820 of pusher 800 includes a second guidance block 880. Guidance blocks 870, 880 are configured to engage corresponding guiding surfaces of retention cavity 1000, as discussed below. The engagement between guidance blocks 870, 880 and the corresponding guiding surfaces of retention cavity 1000 is configured to guide the movement of pusher 800 retained at least partially within retention cavity 1000. In the illustrated embodiment, an upper surface 872 of guidance block 870 is flush with an upper surface 817 of first body portion 810, and an upper surface 882 of guidance block 880 is flush with an upper surface 827 of second body portion 820.

Guidance block 870 includes a width “w1” disposed parallel to the longitudinal axis “A-A,” and guidance block 880 includes a width “w2” disposed parallel to the longitudinal axis “A-A.” Width “w1” is measured between a proximal surface 870 a and a distal surface 870 b of guidance block 870, and width “w2” is measured between a proximal surface 880 a and a distal surface 880 b of guidance block 880 (FIG. 8 ). Both width “w1” and width “w2” may be between about 0.92 mm and about 1.12 mm (e.g., equal to about 1.02 mm). The heights of guidance blocks 870, 880 may be the same as the heights of first body portion 810 and second body portion 820, respectively. That is, the height “h1” of guidance block 870 may be between about 1.42 mm and about 1.62 mm (e.g., equal to about 1.52 mm), and the height “h2” of guidance block 880 may be between about 1.04 mm and about 1.24 mm (e.g., equal to about 1.14 mm) (see FIG. 10 ).

Accordingly, the height-to-width ratio of guidance block 870 is about 1.5:1, and the height-to-width ratio of guidance block 880 is about 1.1:1. Such large ratios (relative to more traditional pushers) help enable the use of a relatively short pusher 800, which helps enable the use of relatively large fasteners 600 (e.g., 5 mm) in a relatively small diameter “d” end effector 200 (e.g., 12 mm).

Further, in either orientation of double pusher 800 (i.e., first double pusher 800 a and second double pusher 800 b), the height “h1” of upper channel 815 of first body portion 810 is closer to knife channel 401 than upper channel 825 of second body portion 820. Here, upper channel 815 of first body portion 810 may engage a smaller fastener (e.g., a 4 mm staple), while upper channel 825 of second body portion 820 may engage a larger fastener (e.g., a 5 mm staple).

With reference to FIG. 12 , pusher 800 is configured to engage and/or be guided by retention cavity 1000 in a plurality of particular locations. Specifically, pusher 800 includes a first pusher guiding surface or first guiding surface 873 disposed on a proximal surface of guidance block 870, a second pusher guiding surface or second guiding surface 874 disposed on a distal surface of guidance block 870, a third pusher guiding surface or third guiding surface 883 disposed on a proximal surface of guidance block 880, and a fourth pusher guiding surface or fourth guiding surface 884 disposed on a distal surface of guidance block 880.

As shown in FIGS. 5 and 5A (or FIGS. 5-5B), for example, retention cavities 1000 are configured in an angled or herringbone-like pattern along tissue-contacting surface 410 of cartridge assembly 400. Retention cavity 1000 includes corresponding guiding surfaces, which are configured to engage and/or guide the movement of pusher 800 retained at least partially therein. In particular, and with particular reference to FIG. 12 , retention cavity 1000 is defined in part by a first retention guiding surface or first guiding surface 1002 configured to engage or guide first guiding surface 873 of pusher 800, a second retention guiding surface or second guiding surface 1004 configured to engage or guide second guiding surface 874 of pusher 800, a third retention guiding surface or third guiding surface 1006 configured to engage or guide third guiding surface 883 of pusher 800, and a fourth retention guiding surface or fourth guiding surface 1008 configured to engage or guide fourth guiding surface 884 of pusher 800.

The orientation of various parts of pusher 800 enable diameter “d” (FIGS. 2 and 3 ) of loading unit 200 to be smaller than more conventional instruments. For example, diameter “d” of loading unit 200 of the present disclosure may be approximately 12 mm, while the diameter of more conventional loading units may be approximately 15 mm. In other types of loading units, the body portions of the pushers (i.e., the portions that directly support fasteners thereon) include guiding surfaces, which engage corresponding guiding surfaces within retention slots. In the present disclosure, and as discussed above, the guiding surfaces of the pushers are included on guidance blocks 870 and 880 of pushers 800. Since the guiding surfaces are not included (or not solely included) on the body portions of pushers 800, the overall height of pushers 800 can be reduced with respect to previous types of pushers. Since the height of pushers 800 is relatively small, the amount of distance that pushers 800 can travel (i.e., “pusher stroke”) is relatively large. Such a large “pusher stroke” allows larger fasteners 600 (e.g., having a height of about 5 mm) to be used in connection with cartridge assembly 400.

The present disclosure also includes using fasteners 600 having the same height as each other, and/or fasteners 600 having a different height from other fasteners 600. For example, fasteners 600 that are located in an outer row farthest from knife channel 401 of cartridge assembly 400 may have a larger height (e.g., 5 mm) than fasteners 600 (e.g., 4 mm) located in the inner row closest to knife channel 401. The stepped configuration of tissue-contacting surface 410 of cartridge assembly 400 may facilitate the use of fasteners 600 having different heights. Further details of fasteners having different heights, and a stepped tissue-contacting surface are disclosed in commonly-owned U.S. Pat. No. 9,918,717 to Czernik, the entire contents of which are hereby incorporated by reference herein.

It is also envisioned that loading unit 200 is configured for use with alternate pushers. With reference to FIGS. 16 and 17 , alternate embodiments of pushers are shown and are usable with loading unit 200 of the present disclosure. FIG. 16 illustrates a first alternate pusher 900, and FIG. 17 illustrates a second alternate pusher 950. First alternate pusher 900 is similar to pusher 800 as pusher 900 includes a first body portion 910, a second body portion 920, and a bridge 930. Pusher 900 also includes a ramp 935 disposed beneath of and at an acute angle with respect to each upper channel 912, 922 of pusher 900. In contrast to pusher 800, a guidance block 940 of pusher 900 is included on bridge 930.

As shown in FIG. 17 , pusher 950 includes a single body portion 960 such that pusher 950 is configured to engage a single fastener 600. Body portion 960 of pusher 950 includes an upper channel 962, and includes a ramp 970 disposed beneath of and at an acute angle with respect to upper channel 962. Additionally, pusher 950 includes a guidance block 980 extending from both lateral sides of body portion 960.

Loading units 200 using alternate pushers 900, 950 include retention cavities 1000 that are shaped to correspond to the shapes of pushers 900, 950.

The present disclosure also includes methods of performing a surgical procedure using surgical instrument 100 and/or loading unit 200 disclosed herein. For example, a method including using loading unit 200 having a diameter of about 12 mm to eject fasteners having a height of about 5 mm is disclosed. Such methods also include inserting loading unit 200 at least partially through a trocar having a diameter of about 12 mm.

In any embodiment disclosed herein, the fasteners or staples can have an angled orientation in the staple cartridge. This orientation affects how the staple pushers are configured. As a result, the stapling instrument can be arranged for stapling greater tissue thicknesses, or to minimize the overall size of the instrument.

Although a manual stapler is shown in FIG. 1 , any of the embodiments disclosed herein could include a motor, or be attached to a motor, or be part of a robotic surgical system.

While the above description contains many specifics, these specifics should not be construed as limitations on the scope of the present disclosure, but merely as illustrations of various embodiments thereof. Therefore, the above description should not be construed as limiting, but merely as exemplifications of various embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto. 

1. (canceled)
 2. A loading unit configured for engagement with a surgical instrument, the loading unit comprising: a proximal body portion defining a longitudinal axis; an end effector disposed in mechanical cooperation with the proximal body portion, the end effector including a cartridge assembly, the cartridge assembly configured to house fasteners therein; an actuation sled longitudinally translatable within the cartridge assembly; a double pusher disposed within the cartridge assembly and configured to engage at most two fasteners such that the double pusher includes a first upper surface configured to engage a first fastener and a second upper surface configured to engage a second fastener, the first upper surface is included on a first body portion, the second upper surface is included on a second body portion, the double pusher also includes a bridge interconnecting the first body portion and the second body portion, the first body portion including a proximal pusher guiding surface and a distal pusher guiding surface, the second body portion including a proximal pusher guiding surface and a distal pusher guiding surface, each of the first and second upper surfaces being parallel to each other and defining an acute angle with respect to the longitudinal axis; and a double retention cavity disposed within the cartridge assembly and configured to retain the double pusher therein, the double retention cavity includes a first retention guiding surface configured to engage the proximal pusher guiding surface of the first body portion of the double pusher retained therein, and a second retention guiding surface configured to engage the distal pusher guiding surface of the first body portion of the double pusher retained therein.
 3. The loading unit according to claim 2, wherein the double pusher includes a first ramp disposed on the first body portion, the first ramp configured to be engaged by a first angled wedge of the actuation sled.
 4. The loading unit according to claim 3, wherein the double pusher includes a second ramp disposed on the second body portion, the second ramp configured to be engaged by a second angled wedge of the actuation sled.
 5. The loading unit according to claim 4, wherein the first ramp is disposed parallel to the longitudinal axis, and wherein the second ramp is disposed parallel to the longitudinal axis.
 6. The loading unit according to claim 4, wherein the first ramp is disposed directly beneath a portion of the first upper surface of the first body portion and the second ramp is disposed directly beneath a portion of the second upper surface of the second body portion.
 7. The loading unit according to claim 3, wherein a proximal-most portion of the first ramp is disposed at a first distance from a lower surface of the double pusher, and a proximal-most portion of the second ramp is disposed at a second distance from the lower surface of the double pusher, the first distance being different than the second distance.
 8. The loading unit according to claim 2, wherein the first upper surface is disposed at a first height from a lower surface of the double pusher, and the second upper surface is disposed at a second height from the lower surface of the double pusher, the first height being different than the second height.
 9. The loading unit according to claim 2, wherein the acute angle is between 30° and 60°.
 10. The loading unit according to claim 2, wherein the double retention cavity includes a third retention guiding surface configured to engage the proximal pusher guiding surface of the second body portion of the double pusher retained therein, and a fourth retention guiding surface configured to engage the distal pusher guiding surface of the second body portion of the double pusher retained therein.
 11. The loading unit according to claim 2, wherein the bridge interconnects a proximal portion of the first body portion with a distal portion of the second body portion.
 12. The loading unit according to claim 2, wherein an outer-most diameter of the end effector is 12 mm with the end effector in an approximated position.
 13. The loading unit according to claim 2, further including fasteners retained at least partially within the cartridge assembly, at least one of the fasteners having a height of 5 mm.
 14. The loading unit according to claim 2, further including fasteners retained at least partially within the cartridge assembly, all of the fasteners disposed on a first lateral side of the cartridge assembly disposed at an acute angle relative to the longitudinal axis
 15. A double pusher for use with a loading unit of a surgical instrument, the double pusher comprising: a first body portion including a first upper surface configured to engage a first fastener and a first ramp configured to be engaged by a first angled wedge of an actuation sled, the first ramp defining a first longitudinal axis, the first upper surface defining an acute angle with respect to the first longitudinal axis; a second body portion including a second upper surface configured to engage a second fastener and a second ramp configured to be engaged by a second angle wedge of an actuation sled, the second ramp being spaced from and parallel to the first longitudinal axis, the second upper surface being parallel to the first upper surface; and a bridge interconnecting the first body portion and the second body portion.
 16. The double pusher according to claim 15, wherein the double pusher is configured to engage exactly two fasteners.
 17. The double pusher according to claim 15, wherein a first lateral edge of the bridge is in contact with the first body portion, and a second lateral edge of the bridge is in contact with the second body portion.
 18. The double pusher according to claim 15, wherein the first upper surface is disposed along a second axis, and the second upper surface is disposed along a third axis, the second axis being spaced apart from the third axis.
 19. The double pusher according to claim 15, further including a lower surface, wherein a proximal-most portion of the first ramp is disposed at a first distance from a lower surface of the double pusher, and a proximal-most portion of the second ramp is disposed at a second distance from the lower surface of the double pusher, the first distance being different than the second distance.
 20. The double pusher according to claim 15, further including a lower surface, wherein the first upper surface is disposed at a first height from the lower surface, and the second upper surface is disposed at a second height from the lower surface, the first height being different than the second height.
 21. The double pusher according to claim 15, wherein the bridge interconnects a proximal portion of the first body portion and a distal portion of the second body portion. 